Vials are one of the preferred container closure systems used by the pharmaceutical industry due to their extensive clinical history and record of long term stability with a wide variety of drugs. Pharmaceutical drugs including biologics are often first commercially introduced in standard containers such as vials. Additionally the industry has made a significant investment in capital equipment for aseptic vial filling. However, vials require the transfer of the contained drug from the vial to an injection device for delivery to the patient. New container closure systems such as prefilled syringes and cartridges have been introduced that allow direct transfer of the drug from the syringe or cartridge to the patient. Injection devices such as autoinjection devices and pens have been developed to utilize these newer forms of container closure. Because of uncertainty about long-term drug stability, and the extensive manufacturing resources already in place, devices that incorporate standard container closure systems such as vials, prefilled syringes or cartridges are greatly preferred by the pharmaceutical industry over devices that require a custom form of drug containment.
However, vials, prefilled syringes and cartridges are not necessarily the optimum containers for a drug delivery device. This is especially true in the case of delivery devices that deliver relatively high volumes of drugs (2-20 cc) or high viscosity (over 15 cP). Vials, prefilled syringes and cartridges are almost exclusively cylinders made of glass, which imposes design constraints on forces and geometries. Typical syringes and autoinjection devices are limited on the viscosities of drug that can be delivered as well as by the forces that can be applied to the glass container closure systems. New injection devices have been developed including pumps for the delivery of insulin that use custom container closures, but these systems are very expensive, cannot generate high forces or pressures and typically reusable and/or refillable.
Due to factors including stability and time to market, pharmaceutical drugs including biologics are often initially marketed in a lyophilized or powder form or in concentrated liquid form. Such drugs packaged in vials in both liquid and powder formulations can require significant preparation prior to administration. To facilitate the administration of liquid formulations in vials, drugs in vials are often packaged with an empty syringe and multiple needles for aspiration out of the vials and injection into the patient. In the case of powder formulations, an additional diluent or solution vial may be provided to allow for reconstituting the powder drug into solution available for injection.
The risks associated with the preparation and administration of these drug forms are significant. They include the potential for needle stick injury during the reconstitution and administration process as well as errors with improper mixing and inaccurate dose volume or concentration delivered. This presents a real challenge for both trained caregivers and patients preparing and receiving the medication. Similar issues of risk can also apply to the transfer of ready-to-inject drug that must be transferred from a vial to an injection device.
This transfer involves removal of the drug from the vial, measurement of the proper dose, and injection into the patient using a syringe. Incomplete transfer of the full volume of the vial necessitates overfilling of the vial by some 25-30% and the associated waste. Contamination of the drug with non-sterile ambient air that is injected into the vial, or improper sterile technique can cause contamination of the injectable drug.
Accordingly, there continues to exist a need for new and/or improved apparatus and methods for transfer, mixing and injection of drugs from a source vial or vials to a subject.